1. Field of the Invention
The present invention relates to an imaging device, an imaging device drive method, and a recording medium storing an imaging device control program. The imaging device is provided such that an imaging lens or an image sensor is relatively movable in a plane perpendicular to an optical axis of the imaging lens.
2. Description of the Related Art
Imaging devices such as camera modules mounted on digital cameras, video cameras, smartphones, and tablet terminals have spread. The imaging device includes: an imaging lens that forms an image of a subject; and an image sensor that captures the image of the subject, which is formed by the imaging lens, by performing photoelectric conversion for each pixel.
If an imaging device is manufactured, various manufacturing errors occur. For example, in the imaging lens, there are errors such as deviation in a position of a surface and a surface shape. If the imaging lens is formed of a plurality of lenses, there are assembly errors such as errors in positions, intervals, and tilts of the lenses. Further, there are also errors in determining positions of the imaging lens and the image sensor. As might be expected, it is considered that such various manufacturing errors are minimized. For example, if the plurality of lenses is constituted to form the imaging lens, by performing the assembly and regulation while photographing a test chart, the assembly errors are reduced (JP2006-208932A). In a manner similar to the above, errors in determining the positions of the imaging lens and the image sensor and the like are reduced.
In contrast, if various manufacturing errors are intended to be completely eliminated, a yield ratio deteriorates, and this leads to an increase in cost. Therefore, some manufacturing errors should be tolerated. However, if the above-mentioned various manufacturing errors cumulatively occur, this may seriously affect image quality of a photographed image. For example, there may be occurrence of low resolution at some locations on a photographed image or occurrence of distribution in resolution. For example, the distribution in resolution means that resolution is high on one side of a photographed image and resolution is low on the other side thereof.
Hence, recently, there is a known technology of correcting lowering in image quality of a photographed image, which is caused by cumulative manufacturing errors, at a photography step. For example, there is a known method of obtaining a photographed image with uniform resolution on the entire screen by automatically photographing a subject at a plurality of focal positions in response to a photography instruction and synthesizing high-resolution parts of the respective images through image processing (JP2012-222431A).
In an imaging device having a hand shaking correction function, image quality of a photographed image may be improved using a lens (hereinafter referred to as a correction lens) which is movable in a direction perpendicular to the optical axis in order to correct hand shaking. For example, there is a known imaging device that moves the correction lens on the basis of an optically optimal position of the correction lens when the optimal position is calculated in advance by photographing a test chart so as to perform hand shaking correction and that makes the correction lens stationary at the optimal position when hand shaking correction is not performed (JP2006-086586A). There is also an imaging device that corrects lateral chromatic aberration through a correction lens (JP2012-044498A). Further, there is also a known imaging device that improves image quality of a photographed image by moving an eccentric lens group which is movable in a direction perpendicular to the optical axis in a manner similar to that of the correction lens (JP2010-237250A).